Effects of bone density alterations on strain patterns in the pelvis: Application of a finite element model

• Published in: Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine Vol. 223; no. 8; pp. 965 - 979
• Main Authors: Leung, A S O, Gordon, L M, Skrinskas, T, Szwedowski, T, Whyne, C M
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.11.2009; SAGE PUBLICATIONS, INC
• Subjects: Bone density; Bone Density - physiology; Cadaver; Computer Simulation; Cortical bone; Elastic Modulus - physiology; Female; Finite Element Analysis; Finite element method; Fractures; Humans; Iron; Loads (forces); Mathematical analysis; Middle Aged; Models, Biological; Pelvic Bones - physiology; Pelvis; Response surface methodology; Stress, Mechanical; Three dimensional models; Validation studies; Weight-Bearing - physiology; finite element modelling; insufficiency fracture; pelvis; response surface; experimental validation; bone density
• ISSN: 0954-4119; 2041-3033
• DOI: 10.1243/09544119JEIM618

Abstract Insufficiency fractures occur when physiological loads are applied to bone deficient in mechanical resistance. A better understanding of pelvic mechanics and the effect of bone density alterations could lead to improved diagnosis and treatment of insufficiency fractures. This study aimed to develop and validate a subject-specific three-dimensional (3D) finite element (FE) model of a pelvis, to analyse pelvic strains as a function of interior and cortical surface bone density, and to compare high strain regions with common insufficiency fracture sites. The FE model yielded strong agreement between experimental and model strains. By means of the response surface method, changes to cortical surface bone density using the FE model were found to have a 60 per cent greater influence compared with changes in interior bone density. A small interaction was also found to exist between surface and interior bone densities (< 3 per cent), and a non-linear effect of surface bone density on strain was observed. Areas with greater increases in average principal strains with reductions in density in the FE model corresponded to areas prone to insufficiency fracture. Owing to the influence of cortical surface bone density on strain, it may be considered a strong global (non-linear) indicator for insufficiency fracture risk.